Overhead projection apparatus

ABSTRACT

Projection apparatus embodying a housing having a lamp casing therein for projecting a light beam onto a reflective surface that directs the beam upwardly through a film and into a lens assembly for ultimate projection of an image onto a screen, wherein the lens assembly is carried on a telescopic mast that may collapse into the housing and is adjustable to vary the angle of the projected image.

United States Patent 1 Wilson, Jr.

[ 1 Jan. 16, 1973 [54] OVERHEAD PROJECTION APPARATUS [76] Inventor: Harry Howard Wilson, Jr., 106 Wilson Street, Park Forest, Ill. 60606 221 Filed; Oct. 24, 1965 21 Appl. No.: 504,598

[52] U.S. Cl. ..353/99, 353/61, 353/37, 353/98 [51] Int. Cl. ..G03b 21/28 [58] Field of Search...,88/24 OH, 24 P, 24 O, 24 OP, 88/24 R, 24, 24 CA; 240/47; 353/98, 99, 56,

[56] References Cited UNITED STATES PATENTS 2,859,660 11/1958 Lucas ..353/37 X 3,059,529 10/1962 Lucas ..353/37 X 3,241,439 3/1966 Kiner et a1. ..353/ 6l X 3,317,151 5/1967 ....353/95 3,472,589 10/1969 ....353/98 3,124,035 3/1964 ....353/99 3,334,957 8/1967 Field ..350/203 Primary Examiner-Samuel S. Matthews Assistant ExaminerRichard M. Sheer Attorney-Martin Faier [57] ABSTRACT Projection apparatus embodying a housing having a lamp casing therein for projecting a light beam onto a reflective surface that directs the beam upwardly through a film and into a lens assembly for ultimate projection of an image onto a screen, wherein the lens assembly is carried on a telescopic mast that may collapse into the housing and is adjustable to vary the angle of the projected image.

3 Claims, 7 Drawing Figures PATENTEDJAI 16 1913 3.711. 194

' sum 1 [IF 4 INVENTOR Harry Howard Wilson Jr PATENTEDJAH 16 1973 I 3.711.194

SHEET 2 OF 4 INVENTOR. Harry Howard Wilson Jr Any PATENTEDJAN 16 I973 3.711.194

SHEET '4 OF 4 r-v-+; L

INVENTOR Harry Howard Wilson Jr W Hm OVERHEAD PROJECTION APPARATUS This invention relatesto improvements in overhead projection apparatus, and is more particularly concerned with the novel construction and assembly of such apparatus.

The present invention is concerned with apparatus of a character that has a housing within which is mounted a light source. The housing has a translucent screen and an overhanging panel forming its top wall. A film or roll of cellophane or acetate is arranged to have its web drawn over the panel-screen combination. Writing or other indicia is drawn on the web so that when the light source is illuminated, the image of the writing or other indicia is projected upwardly. Disposed above the panel screen assembly and spaced a selected distance therefrom to receive the projected image beam is a lens assembly that projects the image beam in a substantially horizontal plane onto a viewing screen. The housing also houses a blower for generating an air stream for cooling the light source and the lens assembly beneath the panel screen combination or stage. The lens assembly above the stage is readily pivotally adjustable to focus and direct the projected image onto a viewing surface, and may be vertically fixed or vertically adjustable so that when the apparatus is not in use the lens assembly can be lowered onto the top surface of the housing and suitable covers hingedly connected to said housing enclose the entire unit. 7

It is therefore an object of the invention to provide a novelly constructed overhead projection apparatus.

Another object is to provide novel cooling means for the light source.

Another object is to provide a novelly constructed lens assembly.

Another object is to provide a novel collapsible support mast for the lens assembly.

Another object is to provide an apparatus of the character referred to which is not expensive to manufacture and assemble, may be collapsed into compact form, and is very efficient and easy to use.

The structure by means of which the above noted and other advantages and objects of the invention are attained will be described in the following specification, taken in conjunction with the accompanying drawings, showing a preferred embodiment of the invention illustrated therein, in which:

FIG. 1 is a perspective view of the apparatus set up for use.

FIG. 2 is a perspective view of the apparatus showing the mast collapsed.

FIG. 3 is a transverse vertical sectional view of the housing, taken substantially on line 3 3 of FIG. 1.

FIG. 4 is a horizontal section view taken substantially along line 4 4 of FIG. 3.

FIG. 5 is a detail view of the mast mounting.

FIG. 6 is a detail sectional view of the mast adjustment means, taken along line 6 6 of FIG. 1.

FIG. 7 is a detail elevational view, partly in section, of the lens assembly.

Referring to the exemplary disclosure of the apparatus as shown in the accompanying drawings, in which like characters refer to like parts, said apparatus includes a base 11 upon which is removably mounted,

firmly, a housing 12. The housing is substantially box shaped and it has mounted therein a mirror 13 disposed at an angle of 45 so as to project a light beam issuing from a light source, generally indicated at 14, upwardly The lens panel assembly constitutes substantially the entire top surface of the housing, and the housing top wall has adjacent to one end of the assembly a wall 16 into which there is'arranged a roll 17 of cellophane, acetate or like material. A suitable cover 18 may be arranged over the well to enclose the roll. The web 17a of said roll is drawn across the top surface of panel 15a and its end is connected to a rewind roller (not shown) contained in an auxiliary casing 19 mounted firmly on the opposite end of the housing. A hand wheel 21 is connected with said rewind roller for rotating the same to advance the web across the top of the stage or lens panel assembly.

The light source 14, best shown in FIGS. 3 and 4, includes a lamp 22 mounted in a socket 23, and said lamp is enclosed in an air tunnel 2 4 defined by a shell 25 having top and bottom and side walls, 61, 62 and 63, respectively, mounted within the housing adjacent to one end. The shell carries a lens 26 in one wall that projects the light beam from the lamp onto'the mirror 13. In order to prevent overheating of the lamp, said shall 25 enclosed an electrically operated blower fan 27 arranged in the path of air flowing into an inlet duct 28 having top and bottom and side walls, 64, 65 and 66, respectively, that communicates with the exterior of the housing through a grill 29. The remote end of the shell 25 opens at 31 into the interior of the housing 12.

The light beam projected upwardly through the Fresnel lens 15 and panel 15a is picked up by a lens assembly, generally indicated at 32, which is disposed above and in vertical alignment with said beam. This assembly is carried on the free end of a forwardly projecting arm 33 on the upper end of a mast 34, which may be telescopic. As shown, the mast is triangular in section and it includes a base section 35 (see FIG. 5) that is secured firmly in the housing 12, as by means of a clamp bracket 36 and a washer .screw assembly 37.

Telescoped into one another and into said base section are two mast sections 38 and 39. The arm 33 has a vertical portion 41 that is telescoped into mast section 39 and has on one apex edge rack teeth 42. Means to finely adjust the position of the lens assembly32 vertically is provided in the form of a pinion 43 that meshes with the rack teeth 42. This pinion is rotatably journalled in a bracket 44 secured firmly to the upper end of mast section 39, and it has a pair of digitally engageable elements 45 thereon to facilitate it being rotated manually. This mast structure is such that the lens assembly may be located in the elevated, in use position shown in FIG. 1, or collapsed into the lowered or non use position shown in FIG. 2. I

The lens assembly 32, best shown in FIG. 7, is comprised on a triangular casing 46 secured firmly to the arms 33 and an adjustable casing 47 pivoted to casing 46, as at 48, so as to be adjustably tilted on'a horizontal axis. The casing 46 has a collector lens 49 in its bottom wall and a lens 51 is carried by-the vertical wall of the casing 47. Mounted within the casing'assembly is a reflector 52 arranged to project an image beam enter- 1 ing through lens 49 onto and through lens 51. for projection onto a viewing screen arranged remote from the apparatus. The reflector 52 is mounted in a frame 53 pivoted at 53a so as to be adjusted angularly in response to tilting of casing 47. Springs 54 arranged between the reflector frame 53 and the casings, providinga resilient mounting between the casing 47 and casing 46 to stabilize and maintain relative adjustment selected between these elements are also included in the assembly. It should be evident at this time that the lens assembly 32 may be adjusted vertically and then casing 47 may be adjusted to dispose the reflector 52 in a manner to project the image beam in a desired direction angularly relative to the horizontal plane.

Whenthe apparatus is set up for use as shown in FIG. 1, writing or other indicia may be made on web 17a lying over panel a. The image of the said indicia is projected upwardly through lens assembly 32 and onto the viewing screen. When collapsed, as shown in the embodiment illustrated in FIG. 2, a pair of covers 55 56 can be swung upwardly and inwardly to overly and enclose the top assembly. One of said covers preferably carried a handle 57.

The overhead projection apparatus disclosed herein may be fully portable, as described, or used in more permanent type installations. In such permanent type installations, mast 34 may be non telescopic, as to eliminate section 38 and mount section 39 directly into bracket 36 and base section 35, and covers 55 56 may likewise be eliminated.

Although I have described a preferred embodiment of my invention in considerable detail, it will be un derstood that the description thereof is intended to be illustrative only, rather than restrictive, as many detailsof the structure disclosed herein maybe modified or changed without departing from the spirit or scope of the invention. Accordingly, I do not desire to be restricted to the exactconst'ruction described herein 7 and shown in the accompanying drawings.

lclaim: 1. In overhead projecting apparatus, a housing, a

Fresnel lens and a transparent panel on top of said telescope one section into the other and into the housing, and means adaptable to cover said lens assembly and panel when said adjustable support is telescoped into the housing. 1

2. In projection apparatus, a lens assembly comprising a first casing open on one face, a lens in a second face of said casing, a second casing pivotally mounted for relative adjustment on said first casing, said second casing having an open face matched to the open face of the first casing, a lens in a second face of said second casing, a reflector within said casings mounted for adjustment relative to said casings disposed to reflect a light beam entering the lensof the first casing through the lens of the second casing, and resilient stabilizing meansarranged between the reflector and said casings to maintain selected adjustment of the casings and reflector relative to one another.

3. The projection apparatus recited in claim 2, in which the stabilizing means comprises springs bearing against each casing and said reflector. I 

1. In overhead projecting apparatus, a housing, a Fresnel lens and a transparent panel on top of said housing, a light source in said housing, means in the housing to reflect a light beam from said source upwardly through said lens and panel, an image bearing web overlying said panel, a lens assembly arranged above said panel to receive an image beam projected through said web and project it onto a viewing screen, adjustable telescoped multi-section support means on said housing for said lens assembly adaptable to telescope one section into the other and into the housing, and means adaptable to cover said lens assembly and panel when said adjustable support is telescoped into the housing.
 2. In projection apparatus, a lens assembly comprising a first casing open on one face, a lens in a second face of said casing, a second casing pivotally mounted for relative adjustment on said first casing, said second casing having an open face matched to the open face of the first casing, a lens in a second face of said second casing, a reflector within said casings mounted for adjustment relative to said casings disposed to reflect a light beam entering the lens of the first casing through the lens of the second casing, and resilient stabilizing means arranged between the reflector and said casings to maintain selected adjustment of the casings and reflector relative to one another.
 3. The projection apparatus recited in claim 2, in which the stabilizing means comprises springs bearing against each casing and said reflector. 